Alkylation process



F 9 c. c. CHAPMAN ALKYLATION PROCESS Filed July 6, 1962 :I.. SETTLERFRESH ISOPARAFFIN TOTAL s2 OLEFIN 7 V 22 ACID cooLER l L70 35* l ,4 32)l PROPANE INVENTOR. C. C. CHAPMAN BYW A T TORNE KS 3,233,007 ALKYLATIONPROCESS Charles C. Chapman, liartlesville, Okla, assignor to PhillipsPetroleum Company, a corporation of Delaware Filed July 6, 1962, Ser.No. 208,058 Claims. (Cl. 260--683.48)

This invention relates to an improvement in a liquid phase alkylationprocess involving the alkylation ofalkylatable hydrocarbon, such as anisoparafiin stream, with an alkylating agent, such as an olefin stream,utilizing a liquid catalyst, such as HF acid.

The instant invention is an improvement in the process diclosed in US.application Ser. No. 807,454, of George E. Hays and Fred T. Sherk, filedApril 20, 1959, now abandoned, the subject matter thereof being claimedin continuation-in-part application Ser. No. 267,391, filed March 21,1963. A specific aspect of the disclosed process comprises passing HFacid catalyst, isoparaffin, and olefin in admixture in liquid formupwardly thru an upright alkylation zone under alkylating conditions toform alkylate, passing the efiiuent liquid from the alkylation zone toan overhead settler to separate an upper hydrocarbon phase and a lowerHF acid phase, gravitating the acid phase to a heat exchange zonecommunicating with the lower end of the, alkylation zone, passing thehydrocarbon phase thru a separation zone to recover a stream of alkylateand a stream of isoparaffin containing HF acid, and injecting saidolefin and said stream of isoparaffin at high velocity upwardly into thelower end of said alkylation zone so as to educe HF acid from said heatexchange zone into said alkylation zone. This process completelyeliminates the use of pumps for handling the HF acid, therebyeliminating one of the difliculties and problems in HF alkylation.

The recycle isoparatfin stream in the above-described process has beenfound to contain a substantial amount of HF acid and the mixing of theolefin with this recycle stream before injecting the admixture into thealkylation zone results in some low quality alkylate (before acid iseduced into the reaction zone) due to the presence of such a lowconcentration of acid. This invention is concerned with an improvementin the aforesaid process whereby a higher yield of higher qualityalkylate is produced.

Accordingly, it is an object of the invention to provide an improvedprocess for alkylating an alkylatable hydrocarbon, such :as anisoparafiin, with an olefin in admixture with liquid catalyst, such asHF acid. Another object is to improve the yield of alkylate in such aprocess. A further object is to improve the quality of alkylate in thistype of alkylation process. Other objects of the invention will becomeapparent to one skilled in the art upon consideration of theaccompanying disclosure.

A broad aspect of the invention comprises separately injecting the totalolefin feed directly into, the lower section of the alkylation zone inthe alkylation process of said application so that the olefin portion ofthe feed is admixed with the isoparaffin portion in the presence of thetotal acid catalyst introduced to the reaction zone. This manner ofoperating increases both the yield and quality of the produced alkylate.While the process is particularly applicable to the alkylation ofisobutane with olefins such as propylenes and butylenes, it is alsoapplicable to alkylation of other talkylatable hydrocarbons. Thus, thealkylation reaction can comprise reaction of an isoparafiln with anotheralkylatable material such as isopropyl alcohol, tert-butyl alcohol,secondary butyl alcohol, isopropyl ether, and the like. Likewise, thecorresponding alkyl esters, such as the alkyl halides, sulfates,phosphates, and fluorides of the olefins may be used as the alkylatablematerial with an appropriate or compatible alkylation catalyst. Otherreactions to which the United States Patent 0 M 3,233,007 Patented Feb,1, 1966 invention is applicable include alkylation of a normal paraflinwith an olefin or other alkylatable material, or alkylation of anaromatic hydrocarbon with an olefin or other alkylatable material. k

The alkylation reaction is carried out with the hydrocarbon reactants inliquid phase but the reactants need not be normally liquid hydrocarbons.The reaction conditions can vary in temperature from sub-zero temperature to temperatures as high as several hundred degrees Fahrenheit andcan be carried out at pressures varying from atmospheric to as high as1000 p.s.i. and upward, and at space velocities in the range of 0.1 toabout 20.

A variety of alkylation catalysts can be employed in the alkylationreaction including conventional catalysts such as sulfuric acid,hydrofluoric acid, phosphoric acid; metal halides including aluminumchloride, aluminum bromide, etc; and other liquid alkylation catalysts.In the alkylation of isoparafiins with olefins, a substantial molarexcess of isoparafiin to olefin is employed, usually to provide a ratioof isoparaffin to olefin in the range of 5:1 to 25: 1. Thehydrocarbon-to-catalyst ratio is in the range of 1:1 to 1:10 andpreferably in the higher portion of the range.

A more complete understanding of the invention may be had by referenceto the accompanying schematic flow diagram in which an upright reactionchamber 10 connects a horizontally elongated heat exchanger 12 with ahorizontally elongated settler 14. Column 10 connects with one endsection of the settler and recycle acid column 16 connects with theopposite end of the settler. Straightening veins 18 are positioned insettler 14 to assist in the phase separation of acid and hydrocarbon.The hydrocarbon phase is taken from the upper section of settler 14 thruline 20 and passed to separation equipment described hereinbelow.

Heat exchanger 12 is provided with a cooling coil 22 thru which coolantis circulated to control the temperature of the acid. Recycleisoparaifin containing an appreciable concentration of HF is injectedfrom line 24 thru an eductor 26 upwardly into the reaction column 10 soas to educe acid in sufficient quantity from heat exchangers 12 toprovide the desired acid concentration and cause mixing of the recyclestream with the acid. Eductor 26 is constructed in accordance with theeductor shown in said application Ser. No. 807,454, and comprises aflared section in line 24 terminating in a disc containing holes, eachof which is provided with an injection tube extending upwardly therefromin column 10 to provide a number of high velocity streams of recycleisoparafiin which educe the required amount of acid for the alkylationreaction.

In order to introduce the olefin portion of the feed so that it is mixedwith the other alkylation reactant in an ambient of maximum acidconcentration in the reaction zone, this total olefin stream isintroduced thru line 28 directly into column 10 just above the upperends of the eductor tubes. In this manner reaction between the reactantstakes place under conditions of high acid concentration and excellentmixing conditions.

Fresh isoparatfin to make up for the isoparalfin converted to alkylateis, introduced preferably thru line 30 but this portion of the feed mayalso be alternatively introduced thru line 32,

The hydrocarbon phase in line 20 is split so that a portion passes todepropanizer 32 thru line 34 and the remaining portion passes via line36 to deisobutanizer 38. A propane rich stream passes overhead fromcolumn 32 thru line 40 to condenser 42 in which the condensate passesthin line 44 to a settler 46 from which some HF acid is recovered thruline 48 for recycle. A portion of the propane is recycled as reflux tocolumn 32 via line 50 under the impetus of pump 52 and another portionis passed thru line 54 to stripper 56 to strip off residual acid.Propane passes from stripper 56 to storage thru line 58.

Deisobutanizer 38 separates the isobutane from the alkylate, along witha small concentration of propane, and passes these constituents overheadto line 60 and to cooler 62 from which the cooled steam passes to surgevessel 64. A portion of the isoparaffin stream is passed by pump 66 tocolumn 38 via line 68 for reflux and the remaining portion is passed vialine '70 to line 24 for injection into the alkylation zone.

The bottoms product from column 38 is passed thru line 72 to adebutanizer (not shown) to remove n-butane from the alkylate. Thealkylate is usually then fractionated for specific purposes.

All of the conditions of separation are conventional in the art andfurther detail in respect to the actual column conditions is unnecessaryto an understanding of the invention.

While the invention has been described in connection with the drawingassuming the alkylation of isobutane with one or more olefins, otheralkylation reactants may be substituted. In order to further illustratethe invention, data from two runs, Run No. 1, representing operation inaccordance with the process in application Serial No. 807,454, and RunNo. 2, representing operation in accordance with the invention, arepresented in the table below.

1 HF cntentabout 190M100 bbl. i-Cl recycle.

2 50% propylene; 50% butylenes by volume and in Run 1, added to recycleisobutane containing HF before injecting into the reactor; in Run 2,added to admixture of recycle isobutane and HF catalyst after injectinginto the reactor.

3 To maintain liquid phase.

It can be seen from the above data that injecting the total olefin feeddirectly into the reactor, so as to mix the same with the recycleisobutane in the presence of the total catalyst injected, efiects animprovement in both the quantity and in in the quality of the alkylate.

Certain modifications of the invention will become apparent to thoseskilled in the art and the illustrative details disclosed are not to beconstrued as imposing unnecessary limitations on the invention.

I claim:

1. A process for alkylating an isoparaflin with an olefin comprising thesteps of:

(a) passing HF acid catalyst, isoparaffin, and olefin in admixture inliquid form upwardly thru an upright alkylation zone under alkylatingconditions so as to form alkylate, the molar ratio of isoparaflin toolefin being in the range of :1 to :1;

(b) passing the efiiuent liquid from said zone to an overhead settler toseparate an upper hydrocarbon phase and a lower HF acid phase;

(c) gravitating the acid phase to a heat exchange zone communicatingwith the lower end of said alkylation zone to control the acidtemperature;

(d) passing said hydrocarbon phase thru a separation zone to recover astream of alltylate and a stream of isoparaffin containing HF acidsubstantially free of said olefin;

(e) ejecting said stream of isoparafiin substantially free of olefin athigh velocity upwardly into the lower end of said alkylation zone so asto educe HF acid from said heat exchange zone into said alkylation zone;and

(f) injecting the total olefin feed directly into the high velocitystream of step (e) in the lower section of said alkylation zone,separately from the recycle stream, so as to mix said olefin with saidstream of isoparaffin and residual acid in the presence of total acid.

2. A process for alkylation of an alkylatable hydrocarbon with an olefincomprising the steps of:

(a) passing a liquid HF catalyst capable of effecting said alkylation,said hydrocarbon, and said olefin in admixture in liquid form upwardlythru an upright alkylation zone under alkylating conditions so as toform alkylate, said isoparafiin being in substantial molar excess oversaid olefin;

(h) passing the efiiuent liquid from said zone to a separation zone toseparate alkylate containing unreacted hydrocarbon, and liquid HFcatalyst;

(c) passing the recovered liquid HF catalyst to a heat exchange zonecommunicating with the lower end of said alkylation zone to control thetemperature of the HE catalyst;

(d) passing the alkylate containing said unreacted hydrocarbon to aseparation zone to recover separate streams of alkylate and saidhydrocarbon as recycle containing an appreciable concentration ofresidual catalyst and substantially free of olefin;

(e) ejecting said stream of recycle hydrocarbon substantially free ofolefin at high velocity upwardly into the lower end of said alkylationzone so as to educe said catalyst from said heat exchange zone into saidalkylation zone; and

(f) injecting the total olefin feed directly into the high velocitystream of step (e) in the lower section of said alkylation zone,separately from the recycle stream, thereby mixing said olefin with theinjected recycle stream of said hydrocarbon and residual catalyst in thepresence of total HF catalyst.

3. The process of claim 1 wherein isobutane is alkylated with propyleneand butylenes.

4. The process of claim 3 wherein fresh isobutane is injected inadmixture with the olefins.

5. The process of claim 1 wherein fresh isoparaifin is injected inadmixture with said olefin stream.

References Cited by the Examiner UNITED STATES PATENTS 2,775,636 12/1956Rupp 260683.48 X 3,053,917 9/ 1962 Bergongnou 260683.48 X 3,080,4383/1963 Sailors 260-683.48 3,160,673 12/1964 Black et al. 260683.58

OTHER REFERENCES Hydrofluoric Acid Alltylation, Phillips Petroleum Co.,1964, pp. 1-6.

DELBERT E. GANTZ, Primary Examiner.

ALPHONSO D. SULLIVAN, Examiner.

1. A PROCESS FOR ALKYLATING AN ISOPARAFFIN WITH AN OLEFIN COMPRISING THESTEPS OF: (A) PASSING HF ACID CATALYST, ISOPARAFFIN, AND OLEFIN INADMIXTURE IN LIQUID FORM UPWARDLY THRU AN UPRIGHT ALKYLATION ZONE UNDERALKYLATING CONDITIONS SO AS TO FORM ALKYLATE, THE MOLAR RATIO OFISOPARAFFIN TO OLEFIN BEING IN THE RANGE OF 5:1 TO 25:1; (B) PASSING THEEFFLUENT LIQUID FROM SAID ZONE TO AN OVERHEAD SETTLER TO SEPARATE ANUPPER HYDROCARBON PHASE AND A LOWER HF ACID PHASE; (C) GRAVITATING THEACID PHASE TO A HEAT EXCHANGE ZONE COMMUNICATING WITH THE LOWER END OFSAID ALKYLATION ZONE TO CONTROL THE ACID TEMPERATURE; (D) PASSING SAIDHYDROCARBON PHASE THRU A SEPARATION ZONE TO RECOVER A STREAM OF ALKYLATEAND A STREAM OF ISOPARAFFIN CONTAINING HF ACID SUBSTANTIALLY FREE OFSAID OLEFIN;